Police say the men, all in their 20s, were found with Jonkheid’s cellphone in their possession as well as the spare wheel, battery and radio from the car he had rented while visiting the Western Cape.

Jonkheid, the founder of Johannesburg-based research agency The Consumer Psychology Lab, was in the town of Stellenbosch last week to attend the South African Marketing Research Association’s annual conference.

He disappeared on Friday afternoon and was reported missing by his wife Liezel on Saturday after failing to arrive for his 8am flight back home.

Jonkheid’s body was found later that day, partially burnt and with a gunshot wound to the head.

The four arrested men also face charges of theft of a motor vehicle.